- From: Tab Atkins Jr. <jackalmage@gmail.com>
- Date: Tue, 24 Jun 2014 12:55:10 -0700
- To: Juergen Roethig <roethig@dhbw-karlsruhe.de>
- Cc: www-svg <www-svg@w3.org>
On Tue, Jun 24, 2014 at 12:48 PM, Juergen Roethig <roethig@dhbw-karlsruhe.de> wrote: > Tab Atkins Jr. wrote: >> On Tue, Jun 24, 2014 at 9:00 AM, Juergen Roethig >> <roethig@dhbw-karlsruhe.de> wrote: >>> >>> I may make 1 (one) coordinate system unit be of size 1px, >>> 42px, 4711px, or even just 0.0815px, dependent on the viewbox, scaling of >>> containing elements, and resolution of the output device. And now I get >>> told >>> that I should use a unit "pixel" for that? Incredible! >> >> >> You may be surprised to learn that 1px does not necessarily equal 1 >> device pixel even in normal CSS. It's a screen-independent size based >> on an angular measure. > > No, I will neither be surprised about nor learn that at all, since I already > know that a "device pixel" and a "pixel" might be different. Nevertheless, > on desktop browsers, they very often have the same size. But you might be > surprised to learn that especially on mobile devices (IOS, Android, > whatever), "pixel" and "device pixel" are usually of different sizes - if > those are of the same size, it's just an exception. That's why I regard a > "pixel" usually as a "virtual device pixel" ;-) But as far as I see, I never > wrote "device pixel" in my previous message, I just wrote "pixel", and the > abbreviation "px" should be a synonym for just that. But I am quite sure > that you will neither be surprised about nor learn that at all, since you > already know that ... So, all "transform" does is transform the coordinate space that those units work in. This is identical between CSS and SVG; some SVG presentation attributes just allow px lengths to be specified without a unit, while the CSS properties require units. So yes, your coordinate system unit might be 5px wide *in the untransformed viewport's coordinate space*, but in the local space it's still just 1px, because user coordinates *are* px units when untransformed. Viewbox is a scale/translate transform applied after the other transforms. > ... but I am surprised to learn, just now, about the accuracy, carefulness, > and reliability when making new "standards" in the W3C - so far the "living > standard" of HTML was the best example for that (and yes, I know, the term > "living standard" for HTML is not originating from the W3C), but other > standards seem to adopt those superiour principles as well (irony intended, > or in that case you might even call it sarcasm). Cool story bro. ~TJ
Received on Tuesday, 24 June 2014 19:55:59 UTC